I saw this on a Pinterest-like website, watched a video as to how to wrap it, and immediately made one and started playing with how to tie it. I LOVE this bathing suit and I plan to make one for all of the ladies in my life!
If your fabric is already folded in half (as it is on the bolt at the fabric store, i.e. JoAnn's), leave it folded in half length-wise. Then, fold it in half width-wise. Cut it into a triangle by leaving about 6 inches on the bottom (whre the folds are) and cutting at an angle toward the top corner. Unfolded it should look like the picture. Your triangles will be approx. 54" by 72" at this point.
The place where the triangles meet is where your crotch goes; beyond that, you tie it up around you to show as much or as little as you'd like! It's so versatile!!! This video shows ways to tie the bathing suit! http://www.youtube.com/watch?v=MvtLKXrp_F4